Fundamental study on environmental stress cracking effects in polymer nanocomposites

聚合物纳米复合材料环境应力开裂效应的基础研究

• 批准号: 437333074
• 负责人: Professor Dr.-Ing. Volker Altstädt
• 金额: --
• 依托单位: Lehrstuhl für Verbundwerkstoffe (CCE)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/437333074?language=en
• 关键词: Fundamental; study; environmental; stress; cracking

Environmental stress cracking (ESC) is one of the most common reasons of lifetime shortening for plastic components. The risk of ESC always occurs when the product is subject to the simultaneous effects of mechanical stresses and aggressive fluids that trigger stress cracking. The consequences of the premature failure are often serious and can be life-threatening when the product is used for instance in the medical care. Accordingly, this is considered to be a great challenge to understand fundamentally and based on this to improve the ESC resistance of polymeric materials. Generally, the ESC resistance improves with increasing molecular weight and a broad molecular weight distribution of the polymer matrix. Moreover, the notable preliminary results reveal that the incorporation of nanofillers provides new possibilities to improve the ESC resistance and consequently prolong the service lifetime of the polymers.Therefore, the objectives of this research proposal are to gain a deep understanding of the influence of nanofiller parameters and the molecular parameters on the ESC behavior of the amorphous polymer under various environment conditions (stress cracking agents and ambient temperatures) as well as different challenging mechanical conditions (static and dynamic loading). Polymethylmethacrylate (PMMA) with different molecular weights and molecular weight distributions will be used as polymer matrices. The PMMA will be compounded with different types, sizes, and contents of nanofillers which have spherical (nano-silicon dioxide (SiO2)), rod-like (halloysite nanotubes (HNTs)) as well as platelet-like geometries (commercial and special surface treated layered silicates). By utilizing mechanical, thermal, morphological, optical, rheological, and surface tension analysis methods, it will be possible to correlate the structure-properties relationship of the nanocomposites. The received insights of this analysis will be the key to understanding the ESC behavior of the polymer nanocomposites.

环境应力开裂（ESC）是塑料部件寿命缩短的最常见原因之一。当产品同时受到机械应力和腐蚀性液体的影响时，通常会发生ESC风险，从而引发应力开裂。过早失效的后果通常是严重的，并且当产品用于例如医疗护理时可能危及生命。因此，从根本上理解这一点并基于此提高聚合物材料的ESC抗性被认为是一个巨大的挑战。通常，ESC抗性随着聚合物基质的分子量和宽分子量分布的增加而改善。此外，值得注意的初步结果表明，纳米填料的掺入为改善ESC抗性并因此延长聚合物的使用寿命提供了新的可能性。本研究的目的是深入了解纳米填料参数和分子参数对非晶态聚合物在各种环境条件下ESC行为的影响（应力开裂剂和环境温度）以及不同的具有挑战性的机械条件（静态和动态载荷）。具有不同分子量和分子量分布的聚甲基丙烯酸甲酯（PMMA）将用作聚合物基质。PMMA将与不同类型、尺寸和含量的纳米填料混合，纳米填料具有球形（纳米二氧化硅（SiO2））、棒状（埃洛石纳米管（HNT））以及片状几何形状（商业和特殊表面处理的层状硅酸盐）。通过利用机械，热，形态，光学，流变学和表面张力分析方法，将有可能关联的纳米复合材料的结构-性能关系。该分析的结果将是理解聚合物纳米复合材料ESC行为的关键。